I. Field of the Invention
The present invention relates generally to the field of high pressure pipe cleaning systems. More particularly, the present invention relates to an improved external valve disabler for use with a multi-cylinder pump which allows a hose member to negotiate down a tortuous path within the pipe without stalling or becoming otherwise impeded.
II. Discussion of the Prior Art
Through time, the task of cleaning sewer pipes and other underground conduits has proven to be both laborious and vexing. The difficulty with such cleaning activity is due, in large part, to the relative inaccessibility of the pipes in that the pipes are disposed a fair distance beneath the surface of the earth and meander in a variety of different directions. As such, traversing the interior of the pipes to clean or remove obstructions is particularly burdensome. To date, one of the most popular methods of cleaning and removing obstructions within underground pipes involves passing a rotating auger through the pipe in order to slash through and remove any unwanted build up that may be encountered within the pipe. However, with the advent of PVC and other plastic underground piping, a significant drawback exists with the rotating auger method in that the blades of the rotating auger readily grind through and damage the plastic piping. With the exorbitant costs involved with removing and replacing the damaged pipes, the resulting problems from the use of the rotating auger may far outweigh the initial inconvenience associated with the clogged or dirty pipes.
In an effort to avoid the aforementioned problems with the auger method, an alternate method for cleaning and unclogging such underground pipes has been developed which involves the use of a high pressure pumping system for directing a stream of fluid within the pipe to blast away and flush out any obstruction or unwanted debris encountered therein. To be specific, a high pressure fluid pump is provided having a hose member extending therefrom with a jetter nozzle attached to the distal end of the hose member. The jetter nozzle, when supplied with high pressure fluid from the pump, is designed to generate a plurality of rearward facing propulsion fluid streams for pulling the hose member through the pipe, in addition to a forward facing penetrating fluid stream for blasting away debris within the pipe. In so doing, this method accomplishes the cleaning and removal of obstructions within underground piping without fear of damaging the pipe regardless of its construction. A problem exists, however, due to the meandering and tortuous nature of the underground piping. More particularly, it is oftentimes difficult for the jetter nozzle and hose member to negotiate past sharp turns or bends that are encountered in the underground piping. When such an impediment is encountered, the forward motion brought about by the propulsion fluid streams of the jetter nozzle is overcome and the hose member is incapable of traveling further within the pipe. This, of course, limits the effectiveness of the high pressure pumping system in cleaning and removing obstructions within the pipe.
Various efforts have been undertaken to correct the problem of having the hose member stall within the pipe. One of the most popular approaches is to purposely generate pulsatile pressure surges within the hose member to cause the jetter nozzle to wiggle back and forth in a serpentine manner. The serpentine movement of the jetter nozzle, it has been found, allows the jetter nozzle to negotiate past sharp bends or obstructions so as to overcome such stalling. The generation of pulsatile pressure surges within the hose member can be accomplished through the use of a multi-cylinder fluid pump in conjunction with a valve disabler for selectively disabling one of the inlet valves of the multi-cylinder pump. During normal operation, the multi-cylinder pump functions smoothly at full capacity, employing all cylinders to generate a fluid stream of high frequency pressure pulses within the hose member, wherein the pressure differential between each successive pressure pulse is relatively small. The nature of the fluid stream during normal pump operation (i.e. uninterrupted pressure pulses with a small pressure differential between pulses) allows the hose member to progress smoothly through the pipe in a substantially forward fashion with negligible lateral movement.
Conversely, with a single valve disabled, the multi-cylinder pump generates a fluid stream of interrupted pressure pulses wherein the pressure differential between each successive pressure pulse is relatively high. This fluid stream causes the distal end of the hose member to wiggle laterally back and forth in the desired serpentine manner. Thus, when a sharp bend or obstruction is encountered within the pipe that causes the hose member to become stalled, the valve disabler is employed to disable a single valve within the multi-cylinder pump so as to allow the jetter nozzle to negotiate past the sharp bend or obstruction. Once the stalled condition is overcome, the valve disabler is then used to return the multi-cylinder pump to normal operation such that the jetter nozzle resumes the forward propulsion of the hose member within the pipe.
Referring to FIG. 1, shown is a partial sectional view of a valve disabler 10 of the prior art used to toggle a multi-cylinder pump between normal operation, with all cylinders functioning, and restricted operation, with one cylinder disabled. Valve disabler 10 comprises a valve plug 12, an adjusting plug 14, a handwheel 16, a cover member 18, an adjusting stem 20, a first lock nut 22, a second lock nut 24, a first O-ring 26, and a second O-ring 28. Valve plug 12 has a first engagement portion extending downwardly from a flange portion, a concentrically disposed aperture extending through the longitudinal mid-line the flange portion and the first engagement portion, and a second engagement portion disposed within an upper portion of the concentrically disposed aperture. The first engagement portion is provided with a threaded portion extending along the outer periphery thereof for coupling valve plug 12 within an inlet valve port of a multi-cylinder pump (not shown). The second engagement portion is further provided with a threaded portion for threadedly receiving adjusting plug 14 therein. Adjusting plug 14 has a flange portion, a descending portion extending downward from a lower end of the flange portion, a neck portion extending upward from an upper end of the flange portion, and a concentrically disposed aperture extending through the longitudinal mid-line of the flange portion, the descending portion, and the neck portion. The flange portion extends radially outward from the descending portion and the neck portion. Second O-ring 28 is sandwiched between a bottom surface of the flange portion of adjustment plug 14, an upper surface of the flange portion of valve plug 12, and the outer periphery of the descending portion of adjustment plug 14 so as to minimize the amount of fluid that may leak or seep therebetween during high pressure operations. The descending portion of adjustment plug 14 is further provided with a threaded arrangement about the external periphery thereof for coupling adjusting plug 14 within the flange portion of valve plug 12. The concentrically disposed aperture formed within adjusting plug 14 has a threaded portion extending therealong for engagement with a threaded portion 32 formed along the exterior surface of adjusting stem 20. This threaded engagement allows adjusting stem 20 to be selectively and controllably positioned within adjustment plug 14.
Adjusting stem 20 is a generally elongated rod member having a flange portion 46, an upper portion extending between handwheel 16 and flange portion 46, and a descending portion extending downward from flange portion 46. Flange portion 46 has an increased diameter in relation to the diameters of the descending and upper portions of adjustment stem 20, and is dimensioned so as to be received within a notch formed along a lower edge of the concentrically disposed aperture of adjustment plug 14. The upper portion of adjustment stem 20 has a groove formed therein for accepting first O-ring 26 therein. First and second lock nuts 22, 24 serve to affix the upper portion of adjusting stem 20 to handwheel 16. Cover member 18 is disposed over the top of handwheel 16 to enclose first lock nut 22 and the upper end of adjusting stem 20 therein. The descending portion of adjustment stem 20 is of a greatly reduced diameter relative to the diameters of flange portion 46 and the upper portion of adjusting stem 20 such that adjusting stem 20 can contact a valve assembly 36.
Although a multi-cylinder pump is not shown in FIG. 1, valve assembly 36 of the type employed within an inlet valve of a multi-cylinder pump is provided to illustrate the disabling function of valve disabler 10. Valve assembly 36 includes an external valve cage 38 disposed proximate the lower portion of valve plug 12 which serves to enclose a valve poppet 34, a valve seat 40, and a valve spring 42. During normal pump operation, valve poppet 34 is free to operate within valve assembly 36 subject to the countervailing forces of valve spring 42 and the suction stroke. To be more specific, the normal bias of valve spring 42 forces valve poppet 34 into contact with valve seat 40 in the absence of the suction stroke. During the suction stroke, a vacuum is formed within the cylinder which draws fluid inward toward valve assembly 36 until the bias of valve spring 42 is eventually overcome. When this suction pressure overcomes the bias of valve spring 42, valve poppet 34 is forced away from valve seat 40 and fluid is drawn into the multi-cylinder pump. Following the suction stroke, the resiliency of valve spring 42 returns valve poppet 34 to a closed position against valve seat 40, thereby prohibiting the backward flow of fluid through valve assembly 36 during the return stroke. Valve disabler 10 can effectively override this normal operation by manually twisting handwheel 16 so as to drive the bottom portion of adjusting stem 20 into contact with valve poppet 34, thereby maintaining valve poppet 34 against valve seat 40. During this condition, valve assembly 36 is disabled in that it cannot draw fluid into the multi-cylinder pump during the suction stroke. As such, the pump is forced to operate only on those remaining cylinders which do not have disabled valve assemblies. This, in turn, causes the multi-cylinder pump to produce a fluid stream within the hose member that consists of a low frequency train of pressure pulses wherein the pressure differential between each successive pulse is relatively large. As noted above, this allows the jetter nozzle on the distal end of the hose member to thrash back and forth in a serpentine manner so as to traverse past any obstructions or sharp turns in an underground pipe.
However, several significant drawbacks exist with the aforementioned valve disabler 10 of the prior art. As an initial matter, the construction and design of valve disabler 10 entails substantial production costs, including increased costs for manufacturing the component parts, as well as increased costs for assembling the component parts into each valve disabler 10. With regard to manufacturing costs, valve disabler 10 of the prior art requires a significant amount of machining to prepare the requisite parts, especially in light of the plurality of different diameters that are required for each particular part. For example, adjusting stem 20 requires at least four separate machining activities to render the embodiment shown in FIG. 1, completely aside from the machining involved in producing threaded portion 32. The upper portion of adjusting stem 20, which extends between flange portion 46 and handwheel 16, must be machined having a predetermined diameter. A notch must be further machined within the upper portion of adjusting stem 20 for receiving first O-ring 26. Flange portion 46 must be machined having a diameter substantially greater than the diameter of the upper portion of adjusting stem 20. Finally, descending portion 44 must be machined down from the larger diameter of flange portion 46 such that descending portion 44 can pass concentrically within the center of valve spring 42 to reach valve poppet 34.
Adjustment plug 14 also requires several specific machining operations to yield the concentrically disposed aperture formed therein. More particularly, the concentrically disposed aperture formed within adjusting plug 14 must be machined to have a portion capable of receiving the upper portion of adjusting stem 20, as well as the flange portion 46 of adjusting stem 20. In the same regard, valve plug 12 requires several machining operations to produce the first engagement portion, the flange portion, and the concentrically disposed aperture extending through the longitudinal mid-line of the flange portion and first engagement portion. Moreover, the concentrically disposed aperture formed within valve plug 12 requires further machining to form an upper portion having an enlarged diameter capable of receiving adjustment plug 14, a lower portion having a reduced diameter capable of receiving the descending portion of adjusting stem 20, and a conical middle portion disposed between these upper and lower portions. Once again, such machining translates into increased production costs.
Valve disabler 10 of the prior art also involves increased assembly costs. As noted above, valve disabler 10 entails a multitude of requisite parts, including valve plug 12, adjusting plug 14, handwheel 16, cover member 18, adjusting stem 20, first and second lock nuts 22, 24, and first and second O-rings 26, 28. Therefore, even aside from the costs associated with machining the plurality of parts, a substantial amount of time and labor must be expended to meticulously position and assemble each of the requisite part into a fully operational valve disabler 10. This, of course, is disadvantageous in that such a protracted assembly process translates into increased assembly costs.
The use of a plurality of component parts also raises an increased likelihood that the valve disabler 10 will experience unwanted leaking. In this regard, each requisite part introduces a dimensional tolerance which, when considered cumulatively, causes added difficulty in aligning valve disabler 10 squarely over the valve assembly 36. As such, an increased likelihood exists that adjusting stem 20 will not be accurately positioned over valve assembly 36 so as to sufficiently force valve poppet 34 into valve seat 40 during the disabling mode of operation. This, of course, can translate into further difficulties, such leaking or the ineffective disablement of the valve assembly 36. Similarly, the individual construction of valve plug 12 and adjustment plug 14 raises an increased likelihood that leaking will occur therebetween, notwithstanding the use of second O-ring 28.
Yet another problem exists with the adjusting stem 20 of the prior art. In particular, a problem stems from the tapered design of the descending portion of adjusting stem 20. As can be seen, this descending portion is tapered so as to have a relatively small diameter which effectively reduces the contact area between the terminal end of the descending portion of adjusting stem 20 and the valve poppet 34. With such a reduced contact area, an increased likelihood exists that the adjusting stem 20 may become dislodged or removed from contacting valve poppet 34. Thus, the reduced contact area between adjusting stem 20 and valve poppet 34 may cause valve disabler 10 to operate in an unreliable manner. Due to the time and money investment associated with cleaning underground piping systems, even the possibility of this unreliable behavior is completely unacceptable. Moreover, the tapered nature of the descending portion of adjusting stem 20 creates a likelihood that the adjusting stem 20 will experience stem damage as it engages with the valve poppet 34 and aligns the valve poppet 34 within the valve seat 40. Such damage to the adjusting stem 20 may result in increased replacement costs and other related problems, such as increased down time while working on site.
Valve disabler 10 of the prior art is also rather cumbersome and bulky relative to valve assembly 38 and the multi-cylinder pump itself. In particular, cover member 18 extends approximately 21/7 inches from the side of the multi-cylinder pump when valve plug 12 is fully screwed into the given inlet valve port. Such an arrangement runs directly counter to the ever-increasing desire to conserve space and miniaturize operations. Moreover, this may present potential safety problems in that an increased likelihood exists for inadvertent contact with valve disabler 10 due to the degree to which it extends from the side of the multi-cylinder pump. Such inadvertent contact may result in damage to valve disabler 10 in addition to valve assembly 38.
A need therefor exists for an improved valve disabler for use in selectively disabling a single valve in a multi-cylinder pump so as to allow a hose member to effectively negotiate down a meandering and tortuous path within an underground piping system without stalling or becoming otherwise obstructed. More particularly, a need exists for a valve disabler having a simplified design which requires a minimal number of requisite parts and assembly labor. A need similarly exists for a valve disabler that will not experience leaking during operation. A need furthermore exists for a valve disabler which is economical, requiring a minimal amount of machining to produce each requisite part. A need similarly exists for a valve disabler which can be repeatedly positioned over the valve assembly in an accurate fashion so as to ensure the proper placement of the valve poppet within the valve seat under all circumstances. A further need exists for an improved valve disabler having an increased contact between the bottom of the adjusting stem and the valve poppet to increase the reliability of the valve disabler. A need also exists for a valve disabler having an adjusting stem of increased width and durability so as to minimize the likelihood that the adjusting stem will experience damage during operation. A need also exists for a valve disabler of reduced size so as to minimize the likelihood that the valve disabler will experience inadvertent contact.